Conclusions We demonstrate that immunization with CBL0137 in vivo a replication-defective
and dominant-negative HSV-1 recombinant CJ9-gD TH-302 expressing high levels of gD can induce strong cross-protective immunity against primary and recurrent HSV-2 genital infection and disease in guinea pigs. We show further that the latent viral load of challenge wild-type HSV-2 is significantly reduced in immunized guinea pigs compared with the mock-immunized controls. Collectively, CJ9-gD represents a new class of HSV-1 recombinant, which is avirulent, unable to establish detectable latent infection in vivo, and serves as an effective vaccine against genital HSV infection and disease in both mice and guinea pigs. Methods Animals Female Hartley guinea pigs (300-350 g) were obtained from Charles River Breeding Laboratories (Wilmington, MA). The described animal experiments were conducted according to the protocols approved by the Harvard Medical Area Standing Committee on Animals and the American Veterinary Medical Association. The Harvard Medical School animal management program is accredited Buparlisib chemical structure by the Association for Assessment and Accreditation
of Laboratory Animal Care (AAALAC) and meets National Institutes of Health standards as set forth in “”The Guide for the Care and Use of Laboratory Animals”" (National Academy Press, 1996). Cells and viruses African Green Monkey Kidney (Vero) cells and RUL9-8 cells, a cell line derived from U2OS cells expressing UL9 and the tetracycline repressor (tetR), were grown and maintained in DMEM growth medium as previously described . Wild-type HSV-2 MS strain (ATCC, Manassas, VA) was propagated and plaque assayed on Vero cells. CJ9-gD was derived from CJ83193 by replacing the essential UL9 gene with the HSV-1 gD gene driven by the tetO-containing hCMV major immediate-early promoter . CJ83193 is a replication-defective virus, in which both copies of the HSV-1 ICP0 gene were replaced by DNA sequences encoding the dominant-negative HSV-1 polypeptide UL9-C535C
under control of the tetO-bearing hCMV major immediate-early promoter . CJ9-gD was propagated and plaque assayed in RUL9-8 cells. Immunization and challenge clonidine One set of 8 guinea pigs and one set of 10 guinea pigs were randomly assigned to 2 groups. Animals were either mock-immunized with DMEM (n = 10) or immunized with 5 × 106 PFU of CJ9-gD (n = 8) in a volume of 50 μl s.c. in the right and left upper flank per guinea pig. On day 21 after primary immunization, animals were boosted. At the same time and one day prior to viral challenge, serum was obtained from saphenous veins and stored at -80°C. Six weeks after the initial immunization, the animals were preswabbed with a moist sterile calcium alginate swab (Fisher Scientific, Waltham, MA) and inoculated intravaginally with 100 μl of culture medium containing 5 × 105 PFU of HSV-2 strain MS.